3B · Chapter 8 · consolidation
Practice A
Original cumulative chapter practice to consolidate taught ideas.
Original cumulative chapter practice to consolidate taught ideas. Solutions are available as revealable feedback and in a separate complete answer key. No answer submissions or accounts are required.
Assessment · 18 questions
Questions
Show your thinking; use diagrams when they help. Do not open solutions during your first attempt.
- A1
There are 6 equal trays with 4 counters on each tray. How many counters are there?
Reveal explanation
Answer: 24
6 groups of 4 make 6 × 4 = 24. Or find 5 × 4 and add 4.
6 rows of 4 dots = 24 dots. - A2
There are 7 equal trays with 3 counters on each tray. How many counters are there?
Reveal explanation
Answer: 21
7 groups of 3 make 7 × 3 = 21. Or find 6 × 3 and add 3.
7 rows of 3 dots = 21 dots. - A3
An array has 7 rows, with 3 objects in each row. Split it into smaller arrays and find the total.
Reveal explanation
Answer: 21
7 groups of 3 make 7 × 3 = 21. Or find 6 × 3 and add 3.
7 rows of 3 dots = 21 dots. - A4
Each tray holds 7 counters. How many full trays are required to arrange 28 counters?
Reveal explanation
Answer: 4
Find how many groups of 7 fit into 28: 28 ÷ 7 = 4.
7 rows of 4 dots = 28 dots. - A5
Compute 6 × 10. Explain a strategy using a known fact.
Reveal explanation
Answer: 60
6 groups of 10 make 6 × 10 = 60. Or find 5 × 10 and add 10.
6 rows of 10 dots = 60 dots. - A6
Compute 7 × 5. Explain a strategy using a known fact.
Reveal explanation
Answer: 35
7 groups of 5 make 7 × 5 = 35. Or find 6 × 5 and add 5.
7 rows of 5 dots = 35 dots. - A7
Use two useful multiplication facts to work out 6 × 10. What is the product?
Reveal explanation
Answer: 60
6 groups of 10 make 6 × 10 = 60. Or find 5 × 10 and add 10.
6 rows of 10 dots = 60 dots. - A8
70 counters are shared equally into 7 groups. How many counters are in each group?
Reveal explanation
Answer: 10
Use inverse multiplication: 7 × 10 = 70; therefore 70 ÷ 7 = 10.
7 rows of 10 dots = 70 dots. - A9
Find 6 groups of 6. Can you use 5 groups plus one more?
Reveal explanation
Answer: 36
6 groups of 6 make 6 × 6 = 36. Or find 5 × 6 and add 6.
6 rows of 6 dots = 36 dots. - A10
Find 7 groups of 9. Can you use 6 groups plus one more?
Reveal explanation
Answer: 63
7 groups of 9 make 7 × 9 = 63. Or find 6 × 9 and add 9.
7 rows of 9 dots = 63 dots. - A11
Explain how splitting 7 equal groups of 7 helps you find their total.
Reveal explanation
Answer: 49
7 groups of 7 make 7 × 7 = 49. Or find 6 × 7 and add 7.
7 rows of 7 dots = 49 dots. - A12
42 counters are shared equally into 6 groups. How many counters are in each group?
Reveal explanation
Answer: 7
Use inverse multiplication: 6 × 7 = 42; therefore 42 ÷ 6 = 7.
6 rows of 7 dots = 42 dots. - A13
There are 6 equal trays with 9 counters on each tray. How many counters are there?
Reveal explanation
Answer: 54
6 groups of 9 make 6 × 9 = 54. Or find 5 × 9 and add 9.
6 rows of 9 dots = 54 dots. - A14
There are 7 equal trays with 5 counters on each tray. How many counters are there?
Reveal explanation
Answer: 35
7 groups of 5 make 7 × 5 = 35. Or find 6 × 5 and add 5.
7 rows of 5 dots = 35 dots. - A15
An array has 6 rows, with 8 objects in each row. Split it into smaller arrays and find the total.
Reveal explanation
Answer: 48
6 groups of 8 make 6 × 8 = 48. Or find 5 × 8 and add 8.
6 rows of 8 dots = 48 dots. - A16
Each tray holds 7 counters. How many full trays are required to arrange 21 counters?
Reveal explanation
Answer: 3
Find how many groups of 7 fit into 21: 21 ÷ 7 = 3.
7 rows of 3 dots = 21 dots. - A17
An array has 7 rows of 6 dots. A student says turning it creates 6 more dots. Explain the error and find the total.
Reveal explanation
Answer: 42
Turning an array swaps rows and columns but adds no dots. Both 7 × 6 and 6 × 7 equal 42.
- A18
Without counting individual counters, show two different decompositions for 6 × 5, and explain why both work.
Reveal explanation
Answer: 30
One decomposition is (5 × 5) + (1 × 5) = 30. Another is (3 × 5) + (3 × 5) = 30. The partitions use different group splits but preserve the same product.